Consistency and Homogeneity of Atmospheric Energy, Moisture, and Mass Budgets in ERA5

Author(s)
Johannes Mayer, Michael Mayer, Leopold Haimberger
Abstract

This study uses advanced numerical and diagnostic methods to evaluate the atmospheric energy budget with the fifth major global reanalysis produced by ECMWF (ERA5) in combination with observed and reconstructed top of the atmosphere (TOA) energy fluxes for the period 1985-2018. We assess the meridional as well as ocean-land energy transport and perform internal consistency checks using mass-balanced data. Furthermore, the moisture and mass budgets in ERA5 are examined and compared with previous budget evaluations using ERA-Interim as well as observation-based estimates. Results show that peak annual mean meridional atmospheric energy transports in ERA5 (4.58 +/- 0.07 PW in the Northern Hemisphere) are weaker compared to ERA-Interim (4.74 +/- 0.09 PW), where the higher spatial and temporal resolution of ERA5 can be excluded as a possible reason. The ocean-land energy transport in ERA5 is reliable at least from 2000 onward (similar to 2.5 PW) such that the imbalance between net TOA fluxes and lateral energy fluxes over land are on the order of similar to 1 W m(-2). Spinup and spindown effects as revealed from inconsistencies between analyses and forecasts are generally smaller and temporally less variable in ERA5 compared to ERA-Interim. Evaluation of the moisture budget shows that the ocean-land moisture transport and parameterized freshwater fluxes agree well in ERA5, while there are large inconsistencies in ERA-Interim. Overall, the quality of the budgets derived from ERA5 is demonstrably better than estimates from ERA-Interim. Still some particularly sensitive budget quantities (e.g., precipitation, evaporation, and ocean-land energy transport) show apparent inhomogeneities, especially in the late 1990s, which warrant further investigation and need to be considered in studies of interannual variability and trends.

Organisation(s)
Department of Meteorology and Geophysics
External organisation(s)
European Centre for Medium-Range Weather Forecasts (ECMWF)
Journal
Journal of Climate
Volume
34
Pages
3955-3974
No. of pages
20
ISSN
0894-8755
DOI
https://doi.org/10.1175/JCLI-D-20-0676.1
Publication date
05-2021
Peer reviewed
Yes
Austrian Fields of Science 2012
105206 Meteorology
Keywords
ASJC Scopus subject areas
Atmospheric Science
Portal url
https://ucris.univie.ac.at/portal/en/publications/consistency-and-homogeneity-of-atmospheric-energy-moisture-and-mass-budgets-in-era5(2525de32-6206-4f37-9f61-9be4e578110a).html